1. Field of the Invention
The present invention relates to laminated electronic components, and more particularly, to a laminated electronic component on which information, such as the time of manufacture, a specification, or a manufacturing condition, is indicated.
2. Description of the Related Art
Product information, such as time of manufacture, product lot numbers, and specifications, is often indicated on various electronic components.
For example, Japanese Unexamined Patent Application Publication Nos. 61-158190 (Patent document 1) and 61-232694 (Patent Document 2) disclose related technologies that are applied to printed circuit boards. In Patent Document 1, a plurality of through holes are provided at respective locations of a printed circuit board, and only desired through holes are sealed to provide a predetermined code, such that specific information is indicated. In Patent Document 2, a plurality of locations at which through-holes for indicating specific information are to be provided are predetermined, and through holes are provided at some of the locations in accordance with information to be indicated.
The technologies disclosed in Patent Documents 1 and 2 described above are both directed to printed circuit boards that have no built-in wiring conductors and that, therefore, have no built-in devices.
On the other hand, for example, for laminated electronic components including laminates, such as multilayer ceramic substrates, the laminates have built-in wiring conductors for providing built-in devices. When the technology described in Patent Document 1 or 2 is applied to such laminated electronic components, the following problems arise.
First, in the technologies described in Patent Documents 1 and 2 through-holes are provided. However, the provision of such through-holes in a laminate included in a laminated electronic component makes it impossible to arrange wiring conductors at locations where the through-holes are provided. Thus, regions where wiring conductors can be arranged in the laminate are limited, which prevents miniaturization of the laminated electronic component.
When a laminate is defined by a multilayer ceramic substrate, the through-holes provided therein cause a problem in that a mechanical failure, such as a crack, is more likely to occur.